There is evidence that binge or extreme drinking episodes are associated with neural and cognitive deficits (Courtney &Polich, 2009). Preclinical animal studies have found evidence of neurodegeneration, reduced neurogenesis, and cognitive deficits after extreme ethanol exposure, especially in adolescent animals (Crews &Nixon, 2009). Two brain regions that appear especially sensitive to extreme exposure are the prefrontal cortex (PFC) and hippocampus (Crews &Nixon, 2009), brain regions involved in executive control and long- term memory (Eichenbaum et al., 2007;Miller &Cohen, 2001). Extreme drinking is particularly common among young adults (Ziegler et al., 2005). For example, one common drinking event is to attempt to have at least 21 drinks on one's 21st birthday (Lewis et al., 2009;Neighbors et al., 2005;Neighbors et al., 2006;Rutledge et al., 2008). Young adulthood is also a time of important brain development changes (Brown et al., 2008). There is evidence that alcohol abuse in young adulthood is associated with problems in brain and cognitive development (Clark et al., 2008;Squeglia et al., 2009). Therefore, the effects of extreme drinking might be especially harmful in young adults. However, to our knowledge most research with young adults has been cross-sectional and has not directly and prospectively examined brain and cognitive changes after a single and well-documented extreme drinking episode. The current research will examine whether a single extreme drinking episode in young adults is associated with dysfunctional brain and cognitive changes. We will study naturalistic extreme drinking associated with turning 21 years of age. 70 participants will be scanned at three different time points. We will examine whether after an extreme drinking episode young adults exhibit: 1) decreased focal brain activity in PFC and hippocampus when performing executive control and long-term memory encoding tasks, assessed with fMRI;and 2) loss of PFC and hippocampal gray and white matter, assessed with structural MRI. Overall, the current translational research based on preclinical animal studies and cognitive neuroscience research will provide evidence about the harmful biological and cognitive consequences of extreme drinking in young adults. PUBLIC HEALTH RELEVANCE: The goal of this research is to examine whether extreme drinking in young adults results in neural injury. This research could have important implications for understanding the adverse effects of alcohol on the developing brain.